Hydrogen Storage System

ABSTRACT

A Hydrogen storage system comprising storage elements coupled to each other to form one or more containers disposed in a space having a volume V where the volume of each of the storage elements is much smaller than the volume V resulting in the storage elements experiencing reduced stress at their inner surfaces. Thus, Hydrogen can be stored at relatively high pressure within these storage elements due to the reduced stress experienced by their inner surfaces. Consequently, materials having relatively lower tensile strength and stiffness can be used to construct the storage elements of the Hydrogen storage system. Further, the storage elements can be shaped and sized to conform to a volume of space having an arbitrary shape and dimensions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to hydrogen storage systems fora defined space and more particularly relates to the architecture, size,shape and positioning of such systems for a defined space in vehicles orin storage areas.

2. Description of the Related Art

Hydrogen is increasingly becoming a fuel used in all types of vehiclesincluding bi-fuel vehicles where the other fuel is gasoline. There ishowever a key practical consideration associated with the use ofHydrogen as a fuel for vehicles. The key consideration is the storage ofthe hydrogen fuel itself; this consideration raises several issues. Inparticular, the size, cost of manufacture, and weight of hydrogen tanksare issues that complicate the design and practicability of such tanksAlso, the storage mass of the Hydrogen is itself a key consideration.

A first issue is the size of the tanks relative to the space allocatedto them in vehicles. Current hydrogen fuel tanks store hydrogen at atypical pressure of 200-350 bars where a “bar” is a unit of pressuredefined in terms of kilopascals; that is 1 bar is equal to 100kilopascals or 100 kPa; 1 kPa≡1000 Pa; 1 MPa≡1,000,000 Pa. The “pascal”is a well-known defined unit for the measurement of pressure, internalpressure, stress, Young's modulus (measure of stiffness of an isotropicelastic material), and tensile strength. At a pressure in the range of200-350 bars, the amount of Hydrogen needed to be stored in a Hydrogentank to be comparable to the energy content of a conventional gasolinetank often makes the size of the Hydrogen tank impractically large andin many cases impossible to install in the space allocated for the tankor in available space in the vehicle. Often the only available space isthe trunk of an automobile and in many cases the size of a 200-350 bartank would, for many vehicles, use virtually the entire trunk spacereducing the overall usefulness of the vehicle. Typically, currenthydrogen tanks have dimensions that are nearly the same as thedimensions of the space allocated to them. For example, many tanksoccupy most if not the entire space of a trunk of a vehicle, which isthe space that is usually allocated to such tanks

Current Hydrogen tanks are often cylindrical in shape and thus theirdesign considerations are based on well known laws of physics regardingthe internal pressure experienced by their inner surfaces when suchcylinders contain gas, liquid or other matter. The effect of theinternal pressure experienced by the internal surface of a cylindricaltank is expressed in terms of the stresses in the longitudinal axis ofthe cylinder and the stresses in the tangential directions(perpendicular to the longitudinal axis). The following equations, knownas Kessel's equations, express the two types of stresses (axial stressor σ_(a) and tangential stress or σ_(t)) in terms of p (measurablepressure), D (diameter of cylinder) and s (thickness of the tank walls):

$\begin{matrix}{\sigma_{a} = \frac{p \cdot D}{4 \cdot s}} & (1) \\{\sigma_{t} = \frac{p \cdot D}{2 \cdot s}} & (2)\end{matrix}$

As can be clearly seen from the above equations, the stressesexperienced by the internal surface of the cylinder in the axial andtangential directions are directly proportional to the inner diameter ofthe cylinder. Thus, for relatively large cylinders such as the 200-350bar cylinders, there is increased stress due to the relatively largediameters, D. Because of the resulting higher stresses that occur,relatively strong fibers are needed to construct these tanks Thecylindrical tanks are typically constructed using a relatively thinwalled metallic cylinder reinforced with relatively strong fibers woundon the surface of the cylinder to which some type of polymer has beenapplied. Thus, the wound fibers are embedded in the polymer applied tothe surface of the cylinder to form a FRP (Fiber Reinforced Polymer),which when cured serves as a strong shell adhered to the outer surfaceof the metallic cylinder so as to assist the inner metallic surface ofthe cylinder to withstand the resulting stresses as defined by equations(1) and (2) above.

The fibers used to construct the tanks are usually relatively strongfibers (such as carbon fibers), which have the requisite amount oftensile strength and stiffness to withstand the stresses resulting fromrelatively large diameter dimensions of the tanks The issue with theserelatively strong fibers is their cost. Such fibers although used inmany industrial and commercial products are not made in the quantitynecessary to provide the benefits of the economies of scale typicallyprovided by parts manufactured en masse in relatively high quantities.Carbon fibers and other fibers with comparable physical characteristicsare relatively very expensive and thus the costs of manufacture ofconventional hydrogen tanks are accordingly expensive.

Further, as previously stated, the 200-350 bar tanks do not have anenergy capacity comparable to gasoline tanks Therefore, in order toincrease the energy content of these tanks, the amount of hydrogen perunit volume is increased thus increasing the mass of hydrogen per unitvolume and thus the energy content of the tank; this is done byincreasing the internal pressure at which the Hydrogen is stored withinthe tank. For example, tanks having an internal pressure of 700 bars canbe used. Such tanks will necessarily have more stress applied to theirinner walls because of the increased pressure (See equations 1 and 2above). With increasing pressure comes the need for strong fibers, whichas described above makes the costs of such tanks relatively expensive.

A review of equations 1 and 2 above shows that one approach at reducingthe stress on the inner walls of the 700 bar tanks, is to design tankswith thicker inner walls—that is, increasing s reduces σ. However, atank with thicker inner walls will weigh more than the same tank withthinner inner walls. For storage tanks used in vehicles, the weight ofthe tank is clearly an important factor in the overall fuel efficiencyof the vehicle. Also, in many cases the cost of manufacturing suchthicker wall tanks increases due to the extra cost of additional wallmaterial and modification in the manufacturing process for these tanks.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a Hydrogen storage system comprising Nstorage elements coupled to each other to form one or more containersthat occupy or fit within boundaries of a defined space with boundaries,dimensions, and shape resulting in a volume V where N is an integerequal to 2 or greater. Each of the storage elements has a volume that isa fraction of (or substantially less than) the volume V resulting ineach storage element and the one or more containers having reduceddimensions compared to the dimensions of the defined space of volume V.A fraction of the volume V refers to a volume of space occupied by oneof N storage elements such that all N storage elements fit within theboundaries of the defined space of volume V. Because each of the storageelements has a volume that is substantially less than the overall volumeV, the inner surfaces of each of the storage elements experiencesubstantially less stress compared to the stress experienced by innersurfaces of one storage tank of volume V. That is, the volume of each ofthe storage elements is reduced to a value that allows usage of lesscostly but adequately strong fibers in the construction of such storageelements. As a result, the reduced stress experienced by the innersurfaces of each of the storage elements allows the usage of fibermaterial (e.g., Innegra, Basalt or other fiber having similar suchproperties) having relatively lower tensile strength and stiffness inthe construction of each such storage element thus reducing the cost ofthe storage system.

The respective volumes of each of the storage elements are notnecessarily equal to each other. For a system having N storage elements,each storage element has a volume defined by dimensions and shape thatmay be the same or different from the other storage elements. When allof the storage elements are coupled to each other to form one or morecontainers, the one or more containers have architectures defined bytheir shape and size and dimensions. All of the storage elements whencoupled together fit in the defined space of Volume V either byconforming substantially to the shape and dimensions of the definedspace or by being able to be disposed totally within the defined spaceof certain dimensions, boundaries and shape resulting in a volume V. Theterms “conforming” or “conform” refer to the one or more containersforming a defined space that has substantially the same shape,dimensions, boundaries and volume, V of the defined space.

Each of the storage elements has an inner layer made of a Hydrogenimpermeable material and an outer layer adhered to the outer surface ofthe inner layer. The outer layer may be a composite material made byfirst applying a resin (e.g., an epoxy resin) onto the outer surface ofthe inner layer and then winding a fiber onto the outer surface at acertain angle with respect to a defined point(s) of reference (e.g.,longitudinal axis of a cylinder) thus embedding the fiber into the resinand allowing the fiber-resin combination to cure to form a relativelyhard shell. Alternatively, the fiber can be wound first onto the outersurface of the inner layer and then a resin is applied; the fiber-resincombination is then allowed to cure to form a relatively hard shell. Yetfurther, the fiber material can be first weaved as a “sock” that is thensnugly fit over the outer surface of the Hydrogen impermeable material.Resin is then applied to the fitted material and allowed to cure to forma relatively hard shell for the storage element. The process of slippingon the “sock” and then adding resin to the sock can be repeated as manytimes as desired. The “sock” refers to fibers weaved into the shape of astorage element so that a snug fit (i.e., a ‘glove’ fit) can be achievedwhen the “sock” is slipped on or over the outer surface of the storageelement made from a Hydrogen impermeable material. Preferably, theHydrogen impermeable material is aluminum or an aluminum alloy and thefiber is made from Basalt, Innegra, or other material with propertiessimilar to Basalt or Innegra. Other Hydrogen impermeable materials andfiber materials that meet design requirements of the storage system ofthe present invention may be used. It will be readily obvious that thestorage system of this embodiment and other embodiments of the presentinvention are not limited to the Hydrogen impermeable material and thefiber materials mentioned above.

In a first embodiment of the storage system of the present invention,all of the storage elements may be coupled to each other to form one ormore containers positioned proximate each other within the boundaries ofthe defined space of volume V where the containers may be different insize, shape and architecture or they may all be the same in size, shapeand architecture.

In a second embodiment of the storage system of the present invention,the storage elements may be coupled to each other to form one or morecontainers each of which is positioned within the boundaries of thedefined space of volume V. Additionally, one or more othercontainers—not formed from storage elements—can also be positionedwithin the boundaries of the defined space of volume V. The containersformed from storage elements and containers not formed from the storageelements all fit within the boundaries of the defined space of volume V.

A particular implementation which can be used for the first and/orsecond embodiments of the present invention comprises storage elementshaving two types of shapes, viz., straight cylinders and bent cylindershaving equal outer diameters (D₀, where 2*r₀=D₀; r₀ is the outer radius)and inner diameters (D_(i), where 2*r_(i)=D_(i); r_(i) is the innerradius); all of the bent cylinders have equal curve radii (r_(c)). Thecurve radius for each of the bent cylinders is equal to k·D₀ (i.e.,r_(c)=k·D₀) where k is a real number greater than zero. Each of the bentand straight cylinders has a volume that is relatively much less thanthe volume V of a defined space within which these storage elements aredisposed. The straight and bent cylinders are coupled to each other toform one or more serpentine cylindrical containers. Also, with thediameter having some measurable thickness so that there is an innerdiameter D_(i) and an outer diameter D₀, the diameter value used in theKessel equations is

$D = {D_{M} = {\frac{D_{0} + d_{i}}{2}.}}$

D_(M) is thus the mid-diameter or average diameter.

For the embodiments discussed above and any other embodiments fallingwithin the claimed storage system of the present invention, thedimensions and shapes of the storage elements and/or containers (madeand/or not made from storage elements) can be varied to construct astorage system in accordance with arbitrary design requirements. Oneparticular set of design requirements puts limits on the size, cost andweight of the storage system. Also, depending on the shape of thedefined space, the design requirements may also dictate the shape of thestorage elements and the shape of containers made or not made from thestorage elements.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings shown in this application represent various embodiments ofthe Hydrogen storage system of the present invention. The variousembodiments are not necessarily drawn to scale and are shown forillustrative purposes to further facilitate the description andexplanation of Hydrogen storage system of the present invention. A briefdescription of the drawings is as follows:

FIG. 1 shows a serpentine cylindrical container of the Hydrogen storagesystem of the present invention;

FIG. 2 shows a straight cylinder section of the serpentine cylindricalcontainer of FIG. 1;

FIG. 2A shows a cross sectional view of FIG. 2 cut along line 2A-2A andalso shows the tangential and axial stress lines due to internalpressure from stored Hydrogen;

FIG. 3 shows a bent cylinder section of the serpentine cylindricalcontainer of FIG. 1;

FIG. 4 shows the straight cylinder section of FIG. 2 with a hardenedshell made of a composite material;

FIG. 5 shows the straight cylinder section of FIG. 2 with a fiber woundthereon at a particular angle;

FIG. 5A is a top view of FIG. 5 and shows the angles formed by linestangential to the wound fiber and the longitudinal axis of the straightcylinder section of FIG. 5;

FIG. 6 depicts a graph that shows the relationships between differentparameters in designing cylinders made from different fibers, havingdifferent diameters, mass and weight, and operated at different internalpressures;

FIG. 7 shows a serpentine cylindrical container with certain dimensions;

FIG. 8 shows one embodiment of the Hydrogen storage system of thepresent invention.

FIG. 9 shows another embodiment of the Hydrogen storage system of thepresent invention where the storage elements are U-shaped;

FIG. 9A shows a front view of FIG. 9 depicting the angular arrangementof the storage elements with respect to each other;

FIG. 10 shows yet another embodiment of the present invention where thestorage elements are capsule shaped;

FIG. 11 shows a generalized embodiment of the storage system of thepresent invention having a volume of arbitrary shape and comprisingthree Sections where each section having three layers;

FIG. 12 shows the individual storage elements of one section of thestorage system of FIG. 11;

FIG. 13 shows an exploded view of the three layers of the sectiondepicted in FIG. 12 and all of the individual storage elements of thatsection; and

FIG. 13A shows how two adjacently positioned storage elements of thesection depicted in FIG. 12 are coupled to each other.

DETAILED DESCRIPTION

The present invention provides a Hydrogen storage system comprising Nstorage elements coupled to each other to form one or more containersthat occupy or fit within boundaries of a defined space with boundaries,dimensions, and shape resulting in a volume V where N is an integerequal to 2 or greater. Each of the storage elements has a volume that isa fraction of (or substantially less than) the volume V resulting ineach storage element and the one or more containers having reduceddimensions compared to the dimensions of the defined space of volume V.A fraction of the volume V refers to a volume of space occupied by oneof N storage elements such that all N storage elements fit within theboundaries of the defined space of volume V. Because each of the storageelements has a volume that is substantially less than the overall volumeV, the inner surfaces of each of the storage elements experiencesubstantially less stress compared to the stress experienced by innersurfaces of one storage tank of volume V. That is, the volume of each ofthe storage elements is reduced to a value that allows usage of lesscostly but adequately strong fibers in the construction of such storageelements. As a result, the reduced stress experienced by the innersurfaces of each of the storage elements allows the usage of fibermaterial (e.g., Innegra, Basalt or other fiber having similar suchproperties) having relatively lower tensile strength and stiffness inthe construction of each such storage element thus reducing the cost ofthe storage system.

The respective volumes of each of the storage elements are notnecessarily equal to each other. For a system having N storage elements,each storage element has a volume defined by dimensions and shape thatmay be the same or different from the other storage elements. When allof the storage elements are coupled to each other to form one or morecontainers, the one or more containers have architectures defined bytheir shape and size and dimensions. All of the storage elements whencoupled together fit in the defined space of Volume V either byconforming to substantially the shape and dimensions of the definedspace or by being able to be disposed totally within the defined spaceof certain dimensions, boundaries and shape resulting in a volume V. Theterms “conforming” or “conform” refer to the one or more containersforming a defined space that has substantially the same shape,dimensions, boundaries and volume, V of the defined space.

Each of the storage elements has an inner layer made of a Hydrogenimpermeable material and an outer layer adhered to the outer surface ofthe inner layer. The outer layer may be a composite material made byfirst applying a resin (e.g., an epoxy resin) onto the outer surface ofthe inner layer and then winding a fiber onto the outer surface at acertain angle with respect to a defined point(s) of reference (e.g.,longitudinal axis of a cylinder) thus embedding the fiber into the resinand allowing the fiber-resin combination to cure to form a relativelyhard shell. Alternatively, the fiber can be wound first onto the outersurface of the inner layer and then a resin is applied; the fiber-resincombination is then allowed to cure to form a relatively hard shell. Yetfurther, the fiber material can be first weaved as a “sock” that is thensnugly fit over the outer surface of the Hydrogen impermeable material.Resin is then applied to the fitted material and allowed to cure to forma relatively hard shell for the storage element. The process of slippingon the “sock” and then adding resin to the sock can be repeated as manytimes as desired. The “sock” refers to fibers weaved into the shape of astorage element so that a snug fit (i.e., a ‘glove’ fit) can be achievedwhen the “sock” is slipped on or over the outer surface of the storageelement made from a Hydrogen impermeable material. Preferably, theHydrogen impermeable material is aluminum or an aluminum alloy and thefiber is made from Basalt, Innegra, or other material with propertiessimilar to Basalt or Innegra. Other Hydrogen impermeable materials andfiber materials that meet design requirements of the storage system ofthe present invention may be used. It will be readily obvious that thestorage system of this embodiment and other embodiments of the presentinvention are not limited to the Hydrogen impermeable material and thefiber materials mentioned above.

In a first embodiment of the storage system of the present invention,all of the storage elements may be coupled to each other to form one ormore containers positioned proximate each other within the boundaries ofthe defined space of volume V where the containers may be different insize, shape and architecture or they may all be the same in size, shapeand architecture.

In a second embodiment of the storage system of the present invention,the storage elements may be coupled to each other to form one or morecontainers each of which is positioned within the boundaries of thedefined space of volume V. Additionally, one or more othercontainers—not formed from storage elements—can also be positionedwithin the boundaries of the defined space of volume V. The containersformed from storage elements and containers not formed from the storageelements all fit within the boundaries of the defined space of volume V.

A particular implementation which can be used for the first and/orsecond embodiments of the present invention comprises storage elementshaving two types of shapes, viz., straight cylinders and bent cylindershaving equal outer diameters (D₀, where 2*r₀=D₀; r₀ is the outer radius)and inner diameters (D_(i), where 2*r_(i)=D_(i); r_(i) is the innerradius); all of the bent cylinders have equal curve radii (r_(c)). Thecurve radius for each of the bent cylinders is equal to k·D₀ (i.e.,r_(c)=k·D₀) where k is a real number greater than zero. Each of the bentand straight cylinders has a volume that is relatively much less thanthe volume V of a defined space within which these storage elements aredisposed. The straight and bent cylinders are coupled to each other toform one or more serpentine cylindrical containers. Also, with thediameter having some measurable thickness so that there is an innerdiameter D_(i) and an outer diameter D₀, the diameter value used in theKessel equations is

$D = {D_{M} = {\frac{D_{0} + D_{i}}{2}.}}$

D_(M) is thus the mid-diameter or average diameter.

For the embodiments discussed above and any other embodiments fallingwithin the claimed storage system of the present invention, thedimensions and shapes of the storage elements and/or containers (madeand/or not made from storage elements) can be varied to construct astorage system in accordance with arbitrary design requirements. Oneparticular set of design requirements puts limits on the size, cost andweight of the storage system. Also, depending on the shape of thedefined space, the design requirements may also dictate the shape of thestorage elements and the shape of containers made or not made from thestorage elements.

Referring to FIG. 1, there is shown a particular implementation of anembodiment of the present invention wherein a serpentine cylindricalcontainer designed to fit within the base area 12 (with correspondingvolume V) of the trunk of a 2007 Mitsubishi Evo 9, which is a bi-fuelvehicle able to operate on gasoline and/or Hydrogen. The serpentinecylindrical container design is described in the context of a trunk of aMitsubishi Evo 9 for illustrative purposes only. It will be readilyobvious that such an embodiment is not limited to the space defined bythe trunk of the Evo 9 vehicle. It is clear that this embodiment and itsvariations can be used in different types of spaces within automobiles,or storage spaces of different environments. The boundaries of the basearea of the trunk are clearly shown. In addition to the boundaries shownfor the base area of the trunk are boundaries that delineate and definethe volume of the trunk discussed infra. Accordingly, for ease ofexplanation, this embodiment of the Hydrogen storage system of thepresent invention will be described in the context of the trunk space ofthe Mitsubishi Evo 9 vehicle. The design requirements are that aHydrogen storage system capable of storing 3 kg of Hydrogen is to belocated in the trunk of the Mitsubishi Evo 9. The storage system weight,cost and size are to be as low as possible.

Continuing with the description of FIG. 1, the serpentine cylindricalcontainer of FIG. 1 comprises six (6) long straight cylinder sections(36, 38, 40, 42, 44, 46), four (4) short straight cylinder sections (32,34, 48, 50) and nine (9) bent cylinder sections (14, 16, 18, 20, 22, 24,26, 28, 30). The various long, short and bent cylinder sections arearranged as shown in FIG. 1 to form serpentine cylindrical container 10that fits within the spatial boundaries of the trunk of the MitsubishiEvo 9. The inner diameter D_(i) of each of the cylinders (long, short orbent) is 36 mm. Each of the long cylinders is 736 mm in length and theshort cylinders are 336 mm long. Each of the bent cylinders has an arclength of 113.1mm and a curve radius (r_(c)) of 76mm and they are bentto form substantially circular arcs. The curve radius is defined withrespect to the longitudinal axis 220 as mentioned in the description ofFIG. 3. The serpentine storage system of FIG. 1 thus comprises threetypes of storage elements, viz., short cylinders, long cylinders andbent cylinders. The thickness, s, of the cylinders is 1 mm for thisembodiment and other embodiments discussed herein in which aluminum isused to construct the cylinders or storage elements.

Referring to FIG. 2, there is shown a perspective view of a straight(long or short) cylinder section 200 with longitudinal axis 220 havingan inner radius r_(i) (with corresponding inner diameter D_(i)=2·r_(i))and an outer radius r₀ (with corresponding outer diameter D₀=2·r₀).Cylinder section 200 has a thickness 240 of the Hydrogen impermeablematerial (e.g., aluminum) with which it is made. The geometry ofcylinder 200 is the same or similar to the geometry of the long andshort cylinders of FIG. 1. The cylinder 200 is formed through well-knownextrusion processes or other well known cylinder forming or tube formingprocesses.

FIG. 2A shows FIG. 2 cut along lines 2A-2A of FIG. 2 to illustrate thedirection of the axial stress σ_(a) and tangential stress σ_(t) forcesacting on the inner surface of cylinder section 200 due to the internalpressure of stored Hydrogen gas. FIG. 3 shows a bent cylinder storageelement 300 having the same inner radius (r_(i)), outer radius (r₀) andthickness 240 as the straight cylinder storage elements such as cylindersection 200. Bent cylinder storage element 300 has a curve radius r_(c);the curve radius is defined with respect to the longitudinal axis 220 asshown. The curve radius, r_(c), is equal to k·D₀ where k is a realnumber greater than zero; for this embodiment k=2; this relationshipdefines the degree of bending that can be performed on a cylinder. Thevalue of k=2 is currently the state of the art in aluminum bendingtechnology. The geometry of bent cylinder storage element 300 is thesame or similar to the geometry of the bent cylinder storage elements ofFIG. 1. Each of the storage elements (bent and straight sections) of theserpentine container is preferably an extruded aluminum section that canbe made from Aluminum alloy 6xxx (for example Aluminum 6061), which hasa certain strength, thickness and density.

The storage elements of short, long and bent cylinders depicted in FIGS.2, 2A and 3 all have circular cross-section as they are clearlycylindrical in shape and geometry. It will be readily obvious to oneskilled in this art that the present invention may also comprise storageelements of the claimed storage system having cross section profilesthat are rectangular, elliptical, diamond shaped and various other crosssections that are not circular.

The volume V of the available trunk space of the 2009 Mitsubishi Evo 9is 430 dm³. The formula for the volume of a cylinder (bent or straight)of length L, diameter D_(M) (where D_(M)=2r_(M);

$r_{M} = \frac{r_{0} + r_{i}}{2}$

and thickness s has a volume V_(cyl)=πr_(M) ²L or

$\frac{D_{M}^{2}}{4}{L.}$

The inner surface of a cylinder experiences stress from the pressure, p,of the stored Hydrogen in accordance with the axial and tangentialstress equations (1) and (2) above which are hereby reproduced below forease of reference:

$\begin{matrix}{\sigma_{a} = \frac{p \cdot D}{4 \cdot s}} & (1) \\{\sigma_{t} = \frac{p \cdot D}{2 \cdot s}} & (2)\end{matrix}$

Using the dimensions of the cylinders and the formula for the volume ofa cylinder, the volume for each of the long cylinders is 0.75 dm³. Thevolume for each of the short cylinders is 0.34 dm³ and for each of thebent cylinders is 0.75 dm³. It is clear that the volume of the storageelements (i.e., long cylinders, short cylinders, and bent cylinders) aremuch smaller than the volume V of the defined space, viz., the volume ofthe trunk of the 2009 Mitsubishi Evo 9.

Each of the cylinder storage elements has a hardened shell adhered toits outer surface. The shell is made of a composite material, whichincludes fibers preferably made from Basalt (C² fiber) or Innegra. Oneimplementation of a cylinder storage element with a hardened shell isdepicted in FIG. 4 where cylinder section 200 (made from aluminum) withthickness 240 has a hardened outer shell 280 (i.e., fiber—epoxy resincomposite material allowed to cure) of thickness 260 adhered thereon. Itshould be noted that the thicknesses 240 and 260 of the inner cylindersection 200 and outer shell 280 respectively are not necessarily drawnto scale. The thicknesses may be equal to each other or either thicknessmay be greater or less than the other.

To form the hardened outer shell or outer layer for the bent and/orstraight cylinder sections, an epoxy resin is first applied to the outersurfaces of the extruded aluminum sections; the resin has a certaintensile strength, stiffness and density. A fiber is then wound (at acertain angle with respect to the longitudinal axis of the bent orstraight cylinder) onto the outer surface at a certain angle (preferably54.7°) with respect to the longitudinal axis 220 (or some other point ofreference) of the cylinder. Alternatively, a fiber is first wound (at acertain angle—preferably 54.7°—with respect to the longitudinal axis ofthe bent or straight cylinders) and then the epoxy resin is applied tothe outer surfaces of the extruded aluminum sections. The fibers areinterwoven with each other creating a thickness of fibers.

Referring to FIG. 5, there is shown cylinder section 200 withlongitudinal axis 220 and with fiber 232 wound in the direction shown bycurved arrow 222. The angle at which the fiber(s) is/are wound isobtained as follows. A portion of longitudinal axis 220 is projectedonto the surface of cylinder section 200 resulting in a line 226 definedby at least two points A and B located at the two respective ends ofcylinder section 200. Line 226 is the shortest distance between twoaligned points at each end of the cylinder sections and thus, line 226spans exactly the length of cylinder section 200. Therefore line 226 isparallel to and aligned with longitudinal axis 220. It will be readilyobvious that line 226 intersects the wound fiber 232 at multiple points,some of which are indicated as intersection points 230. At intersectingpoints 230 tangential lines 228 are shown which represent lines drawntangentially to the intersection points in the direction of winding (asshown by the arrows of lines 228) at those points. Each of the resultingtangential lines thus forms an angle with longitudinal axis 220.

FIG. 5A shows a top view of FIG. 5 and fiber 232 is not shown for easeof explanation. The tangential lines 228 in relation to longitudinalaxis 220 and line 226 show the angle—labeled α—formed between thetangential lines 228 and longitudinal axis 220. FIG. 5 shows only onefiber 232 wound around cylinder section 200 for ease of explanation andclarity of illustration only. It will be readily understood that aplurality of fibers can be wound around cylinder section 200 to formcomposite material (i.e., hardened shell) 280 having a certain thickness260 as shown in FIG. 4. As previously stated, for the serpentinecylindrical container of FIG. 1, the angle α is preferably 54.7°.

Another method that can be used to form the hardened outer shell is touse a fiber tubing process. In this process the fiber is first weavedonto a mandrel to follow the shape and dimensions of the mandrel forminga tube or “sock” or a weaved fiber having the shape of the storageelement for which a hardened shell is being constructed. The mandrel hasthe same shape and dimensions as the storage element. The sock (orweaved fiber shape) is then frictionally and/or snugly fit over theouter surface of the storage element. Resin is then added to the fiber.The process can then be repeated with additional layers of fiber (withthe proper adjustments made for the dimensions of the weaved fiber sockor weaved fiber shape) and resin as needed or desired. The layers offibers and resin are then allowed to cure to form the hardened shell.

A fiber primarily made from volcanic rock such as Basalt rock ispreferably used in the storage system of the present invention. Forexample, a Basalt fiber referred to as C² fiber having a mineralogicalcomposition comprises at least is 52% SiO₂, 17% Al₂O₃, 9%CaO, 5% MgO and17% of various other substances typically found in volcanic rock.Depending on the mechanical and chemical properties of the fibers thatare desirable, various adjustments can be made to the composition. Thefiber can also be an Innegra fiber. By using storage elements withreduced dimensions, the need for relatively very strong and expensivefibers is eliminated. Thus, fibers not as strong as the strongest fibers(e.g., carbon, steel or silicon carbide), which have acceptablemechanical and chemical properties (such as the properties of Basalt andInnegra) and are relatively inexpensive become excellent candidates forthe construction of the storage elements and containers used in thestorage system of the present invention. A comparative look at somerepresentative fibers and their relative properties is shown in thetable below:

Tensile Specific Density Stiffness Strength Elongation Strength StrengthPrice [Kg/dm³] [N/mm²] [N/mm²] [%] per density per costs [ 

 /kg] Innegra 0.84 18,000 590 5 702 176 4 DP1000-steel 7.83 210,000 100010 128 18 7 Dyneema 0.97 100,000 3200 3.4 3300 43 77 Vectran 1.4 103,0003000 3.3 2143 48 45 Glass 2.7 80,000 1800 3.5 667 56 12 Basalt 2.7100,000 2150 4 796 159 5 Silicon Carbide 2.5 420,000 3400 0.05 1360 2750 Carbon 1.8 400,000 4500 1 2500 125 20 Aramid 1.5 130,000 3500 2.82333 117 20

The strongest fibers listed in the table above are those with thehighest stiffness and tensile strength, viz., Dyneema, Silicon carbide,and Carbon. These fibers also have some of the highest specificstrengths (or strength per density) in the table. The strength perdensity is the ratio of tensile strength to density, which is highestfor Carbon and Dyneema. However when the strength of a fiber is relatedto its cost, the Basalt and Innegra fibers yield the highest value forthe fibers in the table (specific strength per cost for Basalt is 159and Innegra 176); this is because Basalt and Innegra are the leastexpensive fibers per unit weight (4 Euros per Kg for Innegra and 5 Eurosper Kg for Basalt) of any of the fibers in the table. Therefore, Basalt,Innegra and other fibers with similar strength per cost values becomeexcellent candidates for the storage system of the present inventionbecause the sizes of the storage elements relative to conventionalHydrogen tanks allow the use of fibers that are not as strong as Carbonor Silicon carbide.

Various parameters related to the materials used to construct thestorage elements and/or containers and the geometries of the containersand storage elements have a direct impact on the design of the storagesystem of the present invention. As discussed above, the three mainconsiderations for the Hydrogen storage system of the present inventionare its weight, size and cost. Some of the parameters that directlyimpact the weight, size and cost of the storage system of the presentinvention include choice of fiber material, thickness of the aluminumcylinders (or thickness of Hydrogen impermeable material), fiberfraction, (i.e., the ratio of amount of fiber to the amount of compositematerial made from fiber and epoxy resin) fiber angular positioning onthe inner layer, the pressure at which the Hydrogen is stored and thedimension (in this case, the diameter of the cylinders) of the storageelements.

To design the storage elements and containers, one approach is to vary adimension (say for example diameter, D) of a storage element. Throughthis approach, the varying parameter will determine the value of theparameters that are related to the size, weight and cost of the storageelements. For example, varying one key parameter such as increasing thediameter of the storage elements will decrease the weight of the storageelement per Hydrogen unit and increase the mass of the Hydrogen that canbe stored. This is because the increase in D increases the volume in asquare relationship and increases the stresses in a linear relationship.For example, if D is doubled, the stresses increase by a factor of 2,but the volume increases by a factor of 2² or 4. Thus, the volumeincreases much more than the stresses for the same increase in D;keeping the amount of Hydrogen constant while increasing D results in adecrease of the weight per Hydrogen of the storage system. Clearly,however, the amount of Hydrogen that can be stored increases as D isincreased. An increase in D will increase the stresses accordingly asalready discussed and thus the fiber needed to withstand the resultingstress may be more expensive than what is called for by the designrequirements. FIG. 6 is a chart showing the interrelationships betweenthe diameter of cylinder storage elements, the mass of the cylinders(thus their weight) and the mass of the stored Hydrogen.

Referring to FIG. 7, there is shown the maximum length of a serpentinecylindrical container that can fit within the footprint (and also withinthe volume) of the trunk of the 2007 Mitsubishi Evo 9. The maximumlength is obtained by decreasing the diameter of the cylindrical storageelements. Complying with the requirement that the curve radius is equalto twice the diameter (r_(c)=kD₀=2·r₀), decreasing the diameterdecreases the curve radius thus allowing more long and short sections tobe coupled to each other in the space provided which serves to increasethe overall length of the serpentine cylindrical container. For adiameter of 10 mm, the container shown in FIG. 7 has eight (8) shortcylinders (each 432 mm in length), 18 long cylinders (each 832 mm inlength) and twenty-five (25) curved cylinders (each having a curveradius of 76 mm and a length of 75.4 mm). For cylinders having diametersof 5mm or less, no hardened outer shell is used. Generally, for storageelements in which the volume of such an element is relatively small, noouter shell is used.

A modified version of the already discussed design approach for thestorage system of the present invention is to define ranges for anacceptable minimal mass of Hydrogen and a maximum weight of the storagesystem. The diameter of the storage elements can then be calculated ordetermined to meet these design requirements. It is easily seen that thevalue of the diameter will determine the weight of the storage system,the size of the storage system. Further, the diameter value willdetermine the stress and thus the choice of fiber for the storageelements, which is a significant factor in the overall cost of thestorage system.

Referring now to FIG. 8, there is shown an embodiment in which onecontainer is made from the coupling of storage elements (i.e., straightcylinders and bent cylinders) to each other to form a serpentinecylindrical container 600 and the other two containers 602, 604 arespherical containers not formed from storage elements. The threecontainers are positioned proximate each other and are disposed withinthe boundaries a space 606 of volume V=430 dm³ defined by the boundariesof the trunk of the 2007 Mitsubishi Evo 9.

The storage elements are not necessarily limited to cylinders orelements having circular profiles. Storage elements having rectangular,square, triangular, elliptical, arbitrarily configured profiles andother profiles can be considered as tubes (of various lengths) which canbe coupled to each other to form containers that conform to theparticular shape and contours of a defined space (with definedboundaries) having a volume V and which fit within the boundaries of thedefined space. These tubes may be bent or shaped in various ways so thatthey fit within a particular defined space delineated by boundaries.

Referring now to FIG. 9, there is shown another embodiment 700 of thestorage system of the present invention where each of the storageelements is a U-shaped element 702 that is constructed using a bentcylinder section as in FIG. 3 and two short cylinder sections (similarto FIG. 4) or constructed with an integral one-piece U-shaped section.Whether constructed as a one piece storage element or a three piecestorage element, the cylindrical sections are manufactured in the sameor similar fashion (and made with the same materials) as the cylindricalsections described with respect to FIGS. 2-5A. Each of the U-shapedstorage elements 702 has the same shape and dimensions. However, one caneasily conceive a storage system where all of the storage elements areU-shaped but some or all are of different sizes. Each of the U-shapedstorage elements 702 is connected to a common distribution conduit 704(which may be a cylinder or a pipe or other shape), which serves as acoupling member to all of the U-shaped storage elements 702. Thus, allof the storage elements are coupled to each other via this commonconduit. Another conduit 706 is coupled to the distribution conduit 704as shown. Conduit 706 (similar to conduit 704) can be made and/ormanufactured with the same materials and in the same or similar fashionas the storage elements described with respect to FIGS. 2-5A. Conduits704 and 706 can also be made from any appropriate Hydrogen imperviousmaterial; preferably conduits 704 and 706 can be made from stainlesssteel or the hydrogen impervious material and composite material shelldescribed with respect to the serpentine containers discussed above. Theconduits 704 and 706 may be coupled to each other via a threadedT-connector or other well known threaded connector.

FIG. 9A shows a front view of the storage system of FIG. 9 positioned onor adhered to a flat surface 705. Each of the storage elements 702defines a plane 703 with its U-shape geometry. Thus, each of the storageelements forms an angle θ defined by plane 703 and surface 705. Theparticular value of θ will depend on any number of factors includingvolume V within which the resulting container (comprising a plurality ofU-shaped containers coupled to each other via conduit 704) is disposed.

The embodiment shown in FIGS. 9 and 9A is an example of what is referredto as a “straight pipe” design where each of the storage elements iscoupled to a common conduit (e.g., a pipe) through which Hydrogen gas isdelivered to the various storage elements. Such an arrangement orconfiguration is relatively more conducive to automated manufacturingand assembly. In particular, each of the storage elements and the commonconduit can be made from material similar to the storage elements usedin the serpentine containers discussed above. Further, the assembly ofthe individual storage elements to the common conduit can also beachieved in an automated fashion making the manufacture of such straightpipe designs more efficient and thus relatively less costly than othertypes of designs. Also, the “straight pipe” design is a modular designapproach because one set of storage elements coupled to a common conduitcan be coupled to another similar set. For example, for a given space ofvolume V, the embodiment shown in FIG. 9 can be replicated K times (K isan integer equal to 2 or greater) and each of the K straight pipedesigns can be coupled to another similarly configured straight pipedesign forming a modularized embodiment of the storage system of thepresent invention. Further, different types of “straight pipe” designscan be coupled to each other to form yet another type of modularizedembodiment of the storage system of the present invention.

FIG. 10 shows another straight pipe embodiment of the storage system ofthe present invention where the storage elements 802 are shaped ascapsules and are coupled to a conduit 804 via straight connectors 810.In the example depicted by FIG. 10, there are 16 capsule storageelements. It will be readily understood that the storage system maycontain any number of capsules as necessary to meet a particular designrequirement. At the ends of the conduit 804, the storage elements arecoupled to conduit 804 via right-angled connectors 808. Each of thestorage elements is shaped as a capsule; that is, each element iscylindrical in form, but the ends of the cylinder are semi-spherical inshape. Another conduit 812 is coupled to conduit 804 with the use of aT-connector 806 as shown. Conduit 804, straight connector 810, rightangle connector 808 and T-connector 806 can all be made from stainlesssteel or other appropriate Hydrogen impermeable material; these partscan also be made from the same materials used to construct theserpentine containers discussed above.

The storage system shown in FIGS. 9 and 10 are referred to as “straightpipe” systems because each such system has a conduit (704 in FIGS. 9 and804 in FIG. 10) to which the storage elements are coupled. Such anarrangement or configuration of storage elements is more conducive toautomated assembly. Further, storage systems using the “straight pipe”configuration or arrangement can be modified more quickly.

The various embodiments described above all comprise storage elementsthat are cylindrical in shape and appropriately sized and dimensionedsuch that their relatively small volumes allow the use of relativelyinexpensive materials having relatively lower tensile strength andstiffness to construct them. The following embodiment depicts a storagesystem in which the storage elements are not cylindrical but arearbitrary in shape and dimension and but they have relatively smallvolumes that allow the use of inexpensive materials in theirconstruction. Thus, for the embodiments described above and theembodiment to be discussed below (FIGS. 11-13A) Hydrogen of pressureequal to 700 bars or greater can be stored in such storage systems.

FIG. 11 shows a storage system 900 of the present invention having avolume V of arbitrary shape and dimensions divided into N differentstorage elements, which when coupled to each other as shown form thestorage system shown in FIG. 11. Arbitrary shape and dimensions mean anyspace of volume V, which can be defined by a particular shape withparticular dimensions where such shape and dimensions are created inarbitrary fashion or are created for any conceivable purpose. Each ofthe storage elements has a volume

${V_{i} \leq \frac{V}{N}};$

with i=2, 3, 4, 5, . . . , N and where each such volume V, is relativelysmall (compared to V; i.e., V_(i)<<V) such that the materials andtechniques used in constructing the storage elements described withrespect to FIGS. 1-5A can also be used to construct these storageelements. That is, the storage system of FIG. 11 comprises N storageelements (N is an integer equal to 2 or greater) each having a volumeV_(i) which allows the use of a Hydrogen impermeable material (such asAluminum) with a fiber-resin shell where the fiber can be made from suchmaterials as Innegra, Basalt or materials with properties similar tothose of Innegra and Basalt. When these storage elements are coupledtogether as shown, they form the storage system of the presentinvention, viz., a container having a particular shape and volume. Thewinding of the fiber process or the fiber tubing process described abovewith respect to the construction of the hardened outer shell forcylindrical storage elements can be used to construct the fiber hardenedouter shells of the storage elements for the storage system of FIG. 11.

The particular embodiment shown in FIG. 11 has a shape that conforms tothe shape of the volume V within which this storage system is disposed;that is, the storage system of the present invention has substantiallythe same or similar shape and has substantially the same dimensions asthe available space of volume V so that the storage system can fitwithin the defined space or the storage system defines a space that issimilar to or is exactly the shape and dimensions of the defined space.Because this embodiment of the storage system of the present inventionconforms to the shape of the volume within which it occupies, anefficient use of the volume space can be achieved. The various storageelements are shaped and dimensioned such that when they are all coupledto each other and positioned as shown, the resulting storage systemconforms to the shape of the available volume V. Thus, such anembodiment can be used to replace previous tanks having arbitrary shapesthat were used to contain other fuels such as natural gas, gasoline,liquid fuels and/or other matter. Further, the same space can now beused to store Hydrogen at relatively high pressures (e.g., 700 bars orhigher) for various applications such as a vehicle storage system,storage system for generating electricity, storage system for homeheating, storage system for industrial applications, storage systemsused to transport Hydrogen and other types of storage systems. Thisparticular embodiment of the storage system of the present invention cantake on the exact shape or a similar shape of the tanks used to storethese various fuels. The storage system shown in FIG. 11 can bedescribed as having three layers L₁, L₂, and L₃ and three sections S₁,S₂ and S₃ as shown. Thus, the storage elements are coupled to each otherto form a container comprising one or more sections.

Referring now to FIG. 12, the storage system of FIG. 11 is shown with adetailed depiction of section S₁. As with the other sections, Section S₁comprises three layers 902, 904 and 906, which are portions of layersL₁, L₂, and L₃ respectively. As shown for this specific storage system,each of the layers (902, 904 or 906) comprises seven (7) storageelements coupled together via openings in the same or similar manner asthe storage elements of the serpentine storage elements discussed above.Layer 902 of section S₁ comprises storage elements 902A, 902B, 902C,902D, 902E, 902F and 902G. Layer 904 of section S₁ comprises storageelements 904A, 904B, 904C, 904D, 904E, 904F and 904G. Layer 906 ofsection S₁ comprises storage elements 906A, 906B, 906C, 906D, 906E, 906Fand 906G.

Referring now to FIG. 13, an exploded perspective view of section S₁ isshown. More particularly, FIG. 13 illustrates how each of the layersforms a portion of section S₁. Referring temporarily to FIG. 13A, thereis shown how storage element 902A is coupled to 902B via openings 903Aand 903B. The openings at which the storage elements 902A and 902B arecoupled can be tapered in complementary fashion (not shown) to promotecoupling. Another embodiment of this storage system may have a circularopening (not shown) at the side where openings 903A and 903B are locatedand a cylindrical tube can then be used to couple the two storageelements 902A and 902B together. Various other methods and techniquescan be used to properly couple the storage elements to each other. Themethods and techniques shown and discussed do not at all represent theentire set of techniques and methods that can be used to couple thestorage elements of the storage system of the present invention to eachother. It should be noted that sections of storage elements orindividual storage elements are said to be “coupled” to each other whentheir openings align with each other to define a container for Hydrogenwith virtually no leakage. However, storage elements which are attachedto each other or which are positioned in relatively close proximity toeach other mean storage elements that are placed physically sufficientlyclose to each other but are not necessarily “coupled” to each other.

Referring back to FIG. 13, each of the storage elements of each layerhas at least one opening to allow the coupling of each such storageelement to adjacently positioned storage elements of that layer. It willbe clear from a review of FIGS. 12 and 13 that except for storageelement 902A, each of the storage elements 902B-902G has two openings.Further, storage element 902G couples to storage elements of differentlayers and is thus a layer coupling storage element as its opening 1000Aaligns with an opening 1000B of storage element 904G of layer 904. Layer904 comprises storage elements 904A-904G. Similar to layer 902, each ofthe storage elements of layer 904 has two openings. Storage element904A, however, is also a layer coupling storage element as its opening2000A is aligned with opening 2000B of storage element 906A of layer906. Layer 906 comprises storage elements 906A-906G. When the threelayers 902, 904 and 906 are coupled to each other via the layer couplingstorage elements as discussed, they define a space or section S₁. Asimilar arrangement can be constructed in sections S₂ and S₃ and allthree sections can be coupled (S₁ to S₂ and S₂ to S₃) to define theoverall space of this embodiment of the storage system of the presentinvention. For example, section S₁ can be coupled to section S₂ viaopenings (not shown) at particular adjacently positioned storageelements from sections S₁ and S₂. Further, section S₂ can then becoupled to section S₃ also via openings (not shown) at particularadjacently positioned storage elements from these two sections. Thethree sections can be coupled as described above and positioned in closeproximity to each other (or attached to each other) to form the storagesystem of the present invention as depicted in FIG. 11. Thus a pluralityof the N storage elements are coupled to each other to form one or moresections each of which is coupled to another section and can be attachedor positioned in relatively close proximity to each other so that allthe sections fit within the space of volume V having an arbitrary shapeand dimensions that conform to the shape of the embodiment of thestorage system of the present invention as shown in FIG. 11. The coupledsections S₁, S₂, and S₃, form a container, which conforms to the shapeand dimensions of the defined space of volume V. The coupled sectionsmay form more than one container all of which when coupled together mayconform to the shape and dimensions of the defined space of volume Vand/or may fit within the boundaries of the defined space of volume V.

The storage system of the present invention has been described in termsof storage elements that are coupled to each other to form containerswithin which Hydrogen is stored to power vehicles. It will be readilyobvious however that the Hydrogen storage system of the presentinvention can be used for storage systems for various other applicationssuch as storage systems for vehicles used to distribute Hydrogen torefill stations. These vehicles transport large amounts of Hydrogen inlarge tanks; the storage system of the present invention can be used toreplace these large tanks The transported Hydrogen is delivered torefill stations for vehicles and is stored in storage tanks at thoselocations. Further the transported Hydrogen can be delivered tohouseholds or places of business, which use the delivered Hydrogen forheating systems and electricity generating systems. The storage systemof the present invention can thus be used to transport Hydrogen todistribute the Hydrogen to refill stations. The present invention can beused to store Hydrogen at the refill stations. Further, the storagesystem of the present invention can be used to store Hydrogen inhouseholds or commercial buildings for heating or for generatingelectricity. Yet further, containers built in accordance with thestorage system of the present invention and which are located at powerstations can be used to generate electricity.

The storage system of the present invention has been described in termsof the various embodiments disclosed herein. It will be readilyunderstood that the various embodiments discussed do not at all limitthe scope of the present invention. One of ordinary skill to which thepresent invention belongs can, after reading this specification and theclaims, implement the storage system of the present invention usingother embodiments and implementations that are different from thosedisclosed herein but which are well within the scope of the claimedhydrogen storage system of the present invention.

What is claimed is:
 1. A Hydrogen storage system to be disposed within adefined space of volume V, the hydrogen storage system comprising: Nstorage elements coupled to each other to form one or more containersthat fit within the defined space where each storage element has avolume equal to a fraction of the volume V and N is an integer equal to1 or greater.
 2. The Hydrogen storage system of claim 1 where each ofthe storage elements has a volume and shape that are the same as otherstorage elements.
 3. The Hydrogen storage system of claim 1 where someor all of the storage elements have different volumes and shapes.
 4. TheHydrogen storage system of claim 1 where each of the storage elementshas an inner layer made of hydrogen impermeable material and an outerlayer made from a composite material.
 5. The Hydrogen storage system ofclaim 1 further comprising one or more other containers not made fromcoupled storage elements and the one or more other containers arepositioned proximate the one or more containers such that both types ofcontainers fit within the defined space of volume V.
 6. The Hydrogenstorage system of claim 1 where the storage elements comprise longcylinders, short cylinders and bent cylinders all of which have an innerlayer with equal inner and outer diameters and with corresponding innerand outer surfaces and where such inner layer is made from aluminum of acertain thickness.
 7. The Hydrogen storage system of claim 6 where thebent cylinders are curved cylinders with a curve radius equal to k·D₀where k is an integer equal to a real number greater than zero and D₀ isthe outer diameter of the bent cylinder.
 8. The Hydrogen storage systemof claim 7 where k is equal to
 2. 9. The Hydrogen storage system ofclaim 6 where the long cylinders, short cylinders and bent cylinders arecoupled to form a serpentine cylindrical container having the innerlayer and an outer layer made of a composite material adhered to theouter surface of the inner layer.
 10. The Hydrogen storage system ofclaim 9 where the outer layer comprises resin applied to the outersurfaces of the inner layer and Basalt fibers wound onto the resinapplied to the outer surfaces of the inner layer at a 45 degree anglewith respect to a longitudinal axis of each of the coupled storageelements.
 11. The Hydrogen storage system of claim 9 where the outerlayer comprises resin applied to the outer surfaces of the inner layerand Innegra fibers wound onto the resin applied to the outer surfaces ofthe inner layer at a 45 degree angle with respect to a longitudinal axisof each of the coupled storage elements.
 12. The Hydrogen storage systemof claim 9 comprising a plurality of serpentine containers positionedproximate each other to fit within the defined space of volume V. 13.The Hydrogen storage system of claim 6 where the long cylinders, shortcylinders and bent cylinders are coupled to form one or more serpentinecylindrical containers and one or more other containers not formed fromthe long cylinders, short cylinders and bent cylinders and all of thecontainers are positioned proximate each other to fit within the definedspace of volume V.
 14. The Hydrogen storage system of claim 13 where theone or more other containers are spherical containers.
 15. The Hydrogenstorage system of claim 6 where each of the storage elements has acircular cross section profile.
 16. The Hydrogen storage system of claim6 where the storage elements have different cross section profiles. 17.The Hydrogen storage system of claim 1 where the storage elements arecoupled to each other via a common distribution conduit.
 18. TheHydrogen storage system of claim 17 where the storage elements areU-shaped cylinders.
 19. The Hydrogen storage system of claim 17 wherethe storage elements are capsules.
 20. A Hydrogen storage system to bedisposed within a defined space of volume V having an arbitrary shapeand dimensions, the hydrogen storage system comprising: N storageelements each having a volume equal to or less than $\frac{V}{N}$ whereN is an integer equal to 2 or greater and the storage elements arecoupled to each other to form a container that conforms to the shape anddimensions of the defined space.
 21. The Hydrogen storage system ofclaim 20 where the container comprises one or more sections coupled toeach other and positioned in relatively close proximity to each other orare attached to each other.
 22. The Hydrogen storage system of claim 21where each of the sections comprises a plurality of the N storageelements coupled together.
 23. The Hydrogen storage system of claim 20where each of the storage elements is made from a Hydrogen impermeablematerial having an outer surface to which a composite material isadhered.
 24. The Hydrogen storage system of claim 23 where the compositematerial comprises resin and fibers made from Basalt rock
 25. TheHydrogen storage system of claim 23 where the composite materialcomprises resin and fibers made from Innegra.
 26. A Hydrogen storagesystem to be disposed within a defined space of volume V having anarbitrary shape and dimensions, the hydrogen storage system comprising:N storage elements each having a volume equal to or less than$\frac{V}{N}$ where N is an integer equal to 2 or greater and thestorage elements are coupled to each other to form one or morecontainers that fit within the defined space.
 27. The Hydrogen storagesystem of claim 26 where the one or more containers are coupled to eachother.